Hello everyone i am new to the board and had a question that i was hoping some people can enlighten me on. I own a 2004 c5 that i purchased about a year ago. I have started doing a few things to the car. As of right now i just have the Corsa Xtreme catback exhaust on it. I want to install 3.73 gears and get rid of the stock 2.73. I am having a heck of a time finding what the technical "name" of the rear end in my car. I am also having a hard time finding where i can just find the gears. Everywhere i find it just has the whole carrier with the gears included replacement. Can only the gears be done in corvettes of this year? Any help on the topic would be greatly appreciated. Also any help or suggestions on where to buy them would be great. I do normally purchase through summit.

Thanks,
Jake

 

From what I understand, unless you have a lot of experience building C5 diffs you are going to have trouble. There is quite a bit of measuring and shimming that has to be done.
Do what I did and call Rick Kim at RKT-56. The man is a whiz with our diffs.
If you get the measurements wrong these diffs will whine like crazy.

Rick's website is linked on the left side of this forum.

 

I agree, 100%

 

Thanks i will have to look into that. I just didn't know that it is such a major.

 

The C5 and C6 diffs are not like the old school diffs as far as setting up the gears. Few people have purchased the tools to do this job and gave up due to spending too much $$$ for shims and not having the technical knowledge. Let me know if I can be of service.

 

Thanks for the plug, guys.

 

I just picked up my 2002 A4 last weekend after having its 2:73 gears replaced with 3:42's. First, let me say I am very happy with the upgrade - no buyer remorse at all (even though it was an expensive mod). Now for details that I found while doing my pre-purchase research:

1. Multiple forum posts expressed the opinion that the differential housing for the 2:73 gear set would not accomodate the 3:42 gear set. [My installer - Quality Motor Sports in Lewisville, TX - told me the same thing] So I opted to simply purchase the entire differential. Do enough research to satisfy yourself whether the 2:73 differential housing will happily accept 3:42 gears (or any other gear set for that matter). You'd hate to buy the 3:42 gears only to later learn that you need a new housing, too, and that it would have been much more cost effective (time and money) to have bought the pre-assembled unit in the first place.

2. Quality Motor Sports purchased and installed an RPM Stage 2 unit for my A4. RPM apparently has backlog of orders, and they took over two weeks to ship the Stage 2 unit to my installer. So if the timing of your install is critical, be sure you find out the REAL shipping time for your parts before putting your retrofit in motion.

3. If you have an automatic transmission, you should also consider an aftermarket stall converter. There are lots of arguments about which fitment you will be happiest with (e.g. a 2,400 unit? a 3,000 unit? a 3,600 unit?, etc.). You should consider sharing your expectations and expected driving habits with a knowldegable parts guy or mechanic, and get their opinions before deciding which one to buy.

4. Again based on multiple forum posts and after discussions with local wrenches, I had Quality Motor Sports install a transmission cooler during the differential install. Do your research. Is this something that you will be better off doing? Or not? Again, depends upon a lot of things - driving habits, current configuration planned modifications to your engine, etc. - a cooler may be desireable/important.

5. Last, assuming you have an A4, you will likely want to consider having a tuner to firm up the transmission's shift points. I had this done during the differential install. Wow! The A4 can deliver something much more satisfying than the "slush box" behavior it exhibits in fatory-spec tune.

Just my opinions.

The Lizzard

 

Absolutely Rick
I'm having a riot with the diff you built for me and I have zero whining.
Not to mention you must have burnt the shop down moving around so fast getting my diff ready for me in the time you did.
I'm still waiting for some good warm weather to really play with the new set up, but it's so much fun now I can't imagine the smile on my face when I'm not spinning through second and third gear on a hard pull.

Keep up the good work and hopefully the OP will be in touch with you for some work.

 

 

Good news...

 

there's a good reason for that. C5 carrier gear replacement is not as easy as conventional differentials.

So there's a chance a novice might not get it right the first time.

Since R&R of the carrier (to correct mistakes) is not as simple as on conventional cars.... you do want to get this done - right - the first time.

info here:
www.tim-yvonne.com/mikemercury/342.htm

 

Rear-gear Swap/Differential Rebuild How-To

Sure you can change the gears, but you'll need to pick up the tools to do it properly. I see them on ebay quite often for not too much money. You could probably sell them here on the forum when you're done and get some or all of your money back. Setting up the gears is a bit of work though, so you kind of have to want to do it. If you enjoy this kind of thing, then there's nothing to be afraid of IMHO. The trick is having a supply of various sized side shims and pinion shims so that you can come up with the proper overall thickness for each side. Jaws Gear sells the Motive ring/pinion sets for about $250 if I remember correctly.